Liquid ejecting head and liquid ejecting apparatus

ABSTRACT

A liquid ejecting head includes: a first pressure chamber that applies pressure to a liquid; a second pressure chamber that applies pressure to the liquid; a nozzle channel that extends in a first direction and includes a nozzle that ejects the liquid; a first communication channel that extends in a second direction crossing the first direction and enables the first pressure chamber and the nozzle channel to communicate with each other; a second communication channel that extends in the second direction and enables the second pressure chamber and the nozzle channel to communicate with each other; and a first branch channel that has a portion extending in the first direction and enables the first pressure chamber and the nozzle channel to communicate with each other through a path different from a path of the first communication channel.

The present application is based on, and claims priority from JPApplication Serial Number 2020-074940, filed Apr. 20, 2020, thedisclosure of which is hereby incorporated by reference herein in itsentirety.

BACKGROUND 1. Technical Field

The present disclosure relates to a liquid ejecting head and a liquidejecting apparatus.

2. Related Art

Liquid ejecting apparatuses such as ink jet printers generally have aliquid ejecting head that ejects liquid such as ink. For example, asdisclosed in JP-A-2013-184372, a liquid ejecting head includes apressure chamber that applies pressure to liquid, and a channel thatcommunicates with the pressure chamber and that is provided with anozzle that ejects liquid, and the pressure chamber and the channelcommunicate with each other. According to JP-A-2013-184372, a pluralityof pressure chambers and a plurality of channels are arrayed in a givendirection.

Depending on a shape of a channel extending from a pressure chamber to anozzle, it may be difficult for the pressure to be transferred from thepressure chamber to the nozzle. For example, when the channel extendingfrom the pressure chamber to the nozzle is elongated or is formed to bepartially bent, it is difficult for the pressure to be transferred fromthe pressure chamber to the nozzle. In this case, increasing a sectionalarea of the channel extending from the pressure chamber to the nozzle toreduce channel resistance of the channel is considered for making iteasy to transfer the pressure from the pressure chamber to the nozzle.

However, in a case in which the number of channels extending from thepressure chamber to the nozzle is one as described in JP-A-2013-184372,when the sectional area of the channel increases, a partition wall thatseparates adjacent channels tends to be warped. Therefore, when tryingto efficiently transfer the pressure from the pressure chamber to thenozzle, there has been a problem that structural crosstalk caused bywarping of the partition wall occurs.

Note that “structural crosstalk” refers to a phenomenon that, whenvibration of one of two channels adjacent to each other is transferredto the other channel, ejection characteristics of ink from a nozzleprovided in the other channel are deteriorated.

SUMMARY

To address the aforementioned problem, a liquid ejecting head accordingto a preferred aspect of the disclosure includes: a first pressurechamber that applies pressure to a liquid; a second pressure chamberthat applies pressure to the liquid; a nozzle channel that extends in afirst direction and includes a nozzle that ejects the liquid; a firstcommunication channel that extends in a second direction crossing thefirst direction and enables the first pressure chamber and the nozzlechannel to communicate with each other; a second communication channelthat extends in the second direction and enables the second pressurechamber and the nozzle channel to communicate with each other; and afirst branch channel that has a portion extending in the first directionand enables the first pressure chamber and the nozzle channel tocommunicate with each other through a path different from a path of thefirst communication channel.

A liquid ejecting apparatus according to a preferred aspect of thedisclosure includes: the liquid ejecting head according to theaforementioned aspect; and a control section that controls liquidejection operation of the liquid ejecting head.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating an example of a configuration ofa liquid ejecting apparatus according to a first embodiment.

FIG. 2 is a schematic view of channels of a liquid ejecting headaccording to the first embodiment.

FIG. 3 is a sectional view along line III-III in FIG. 2 .

FIG. 4 is an enlarged sectional view illustrating a portion of theliquid ejecting head illustrated in FIG. 3 .

FIG. 5 is an enlarged sectional view illustrating a portion of a liquidejecting head according to a second embodiment.

FIG. 6 is an enlarged sectional view illustrating a portion of a liquidejecting head according to a third embodiment.

FIG. 7 is an enlarged sectional view illustrating a portion of a liquidejecting head according to a fourth embodiment.

FIG. 8 is a schematic view of channels of a liquid ejecting headaccording to a reference example.

FIG. 9 is a sectional view along line IX-IX in FIG. 8 .

FIG. 10 is a sectional view along line X-X in FIG. 8 .

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Preferred embodiments of the disclosure will be described below withreference to the accompanying drawings. Note that, in the drawings,dimensions or scales of components appropriately differ from actualones, and some components are schematically illustrated for easyunderstanding. The scope of the disclosure is not limited to theembodiments as long as there is no description particularly limiting thedisclosure in the following description.

Note that the following description will be given by appropriately usingthe X-axis, the Y-axis, and the Z-axis that cross each other. The X-axisis an example of “a first axis”. The Z-axis is an example of “a secondaxis”. The Y-axis is an example of “a third axis”. A direction extendingalong the X-axis is referred to as direction X1, and a directionopposite to direction X1 is referred to as direction X2. Similarly,directions opposite to each other along the Y-axis are referred to asdirection Y1 and direction Y2. Directions opposite to each other alongthe Z-axis are referred to as direction Z1 and direction Z2. Thedirection extending along the X-axis is an example of “a firstdirection”. The direction extending along the Z-axis is an example of “asecond direction”. The direction extending along the Y-axis is anexample of “a third direction”. Direction X1 is an example of “one sidein the first direction”. Direction X2 is an example of “another side inthe first direction”. Here, the Z-axis is typically an axis extending inthe up-down direction, and direction Z2 corresponds to the downdirection of the up-down direction. However, the Z-axis may be an axisthat does not extend in the up-down direction. The X-axis, the Y-axis,and the Z-axis are typically orthogonal to each other but are notlimited thereto. They may cross each other at an angle in a range of,for example, 80° to 100°.

A: First embodiment

A1: Overall Configuration of Liquid Ejecting Apparatus

FIG. 1 is a schematic view illustrating an example of a configuration ofa liquid ejecting apparatus 100 according to a first embodiment. Theliquid ejecting apparatus 100 is an ink jet printing apparatus thatejects droplets of liquid such as ink onto a medium 11. The medium 11is, for example, a printing sheet. Note that the medium 11 is notlimited to the printing sheet and may be, for example, a printing objectmade from any material such as a resin film or fabric.

A liquid container 12 is attached to the liquid ejecting apparatus 100.The liquid container 12 accumulates ink. Examples of a specific mode ofthe liquid container 12 include a cartridge detachably attachable to theliquid ejecting apparatus 100, a bag-like ink pack formed from aflexible film, or an ink tank that is able to be replenished with ink.Note that the liquid container 12 accumulates any type of ink.

As illustrated in FIG. 1 , the liquid ejecting apparatus 100 includes acontrol unit 21, a transport mechanism 22, a moving mechanism 23, and aliquid ejecting head 24. The control unit 21 includes, for example, aprocessing circuit such as a CPU (central processing unit) or FPGA(field programmable gate array) and a storage circuit such assemiconductor memory and controls operation of the respective elementsof the liquid ejecting apparatus 100. Here, the control unit 21 is anexample of “a control section” and controls ink ejection operation ofthe liquid ejecting head 24.

The transport mechanism 22 transports the medium 11 in the Y-axisdirection in accordance with control of the control unit 21. The movingmechanism 23 causes the liquid ejecting head 24 to be reciprocated inthe X-axis direction in accordance with control of the control unit 21.The moving mechanism 23 includes a transport body 231 that issubstantially box shaped and that houses the liquid ejecting head 24,and an endless transport belt 232 to which the transport body 231 isfixed. Note that the number of liquid ejecting heads 24 mounted on thetransport body 231 is not limited to one and may be two or more.Moreover, the liquid container 12 described above may be mounted on thetransport body 231 together with the liquid ejecting head 24.

The liquid ejecting head 24 ejects the ink, which is supplied from theliquid container 12, from a plurality of nozzles onto the medium 11 inaccordance with control of the control unit 21. The ejection isperformed in conjunction with transport of the medium 11 by thetransport mechanism 22 and reciprocation of the liquid ejecting head 24by the transport body 23, and thereby, an image is formed on the surfaceof the medium 11.

A2: Channels of Liquid Ejecting Head

FIG. 2 is a schematic view of channels of the liquid ejecting head 24according to the first embodiment. As illustrated in FIG. 2 , the liquidejecting head 24 includes a plurality of nozzles N, a plurality ofindividual channels P, a first common liquid chamber R1, and a secondcommon liquid chamber R2 and is coupled to a circulation mechanism 26.

Specifically, the liquid ejecting head 24 has a surface facing themedium 11, and the plurality of nozzles N are provided on the surface asillustrated in FIG. 2 . The plurality of nozzles N are arrayed in theY-axis direction. The plurality of nozzles N eject the ink in directionZ2.

Here, a set of the plurality of nozzles N constitutes a nozzle row L.The plurality of nozzles N are arrayed at an equal pitch θ. The pitch θis a distance between the centers of the plurality of nozzles N in theY-axis direction.

The individual channels P communicate with the plurality of nozzles N.The plurality of individual channels P extend in the X-axis directionand communicate with the nozzles N that differ from each other. A set ofthe plurality of individual channels P constitutes an individual channelrow 25. The plurality of individual channels P are arrayed in the Y-axisdirection.

As illustrated in FIG. 2 , each of the individual channels P includes apressure chamber Ca, a pressure chamber Cb, and a nozzle channel Nf.Here, the pressure chamber Ca is an example of a first pressure chamber.The pressure chamber Cb is an example of a second pressure chamber. Eachof the pressure chamber Ca and the pressure chamber Cb of the individualchannel P extends in the X-axis direction and is a void that accumulatesthe ink to be ejected from a nozzle N communicating with the individualchannel P. In the example illustrated in FIG. 2 , a plurality ofpressure chambers Ca are arrayed in the Y-axis direction. Similarly, aplurality of pressure chambers Cb are arrayed in the Y-axis direction.Note that, in each of the individual channels P, the position of each ofthe pressure chambers Ca in the Y-axis direction and the position ofeach of the pressure chambers Cb in the Y-axis direction are the same inthe example illustrated in FIG. 2 but may differ from each other. In thefollowing description, when there is no particular necessity todistinguish between the pressure chamber Ca and the pressure chamber Cb,they are simply referred to also as “pressure chambers C”.

The nozzle channel Nf is arranged between the pressure chamber Ca andthe pressure chamber Cb of the individual channel P. In the individualchannel P, the nozzle channel Nf extends in the X-axis direction andconstitutes at least a portion of a channel that enables the pressurechamber Ca and the pressure chamber Cb to communicate with each other. Aplurality of nozzle channels Nf are arrayed with a gap therebetween inthe Y-axis direction. Each of the nozzle channels Nf is provided withthe nozzle N. When pressure in the pressure chamber Ca or the pressurechamber Cb described above changes, the ink is ejected from the nozzle Nof the nozzle channel Nf.

The plurality of individual channels P enable the first common liquidchamber R1 and the second common liquid chamber R2 to communicate witheach other. Each of the first common liquid chamber R1 and the secondcommon liquid chamber R2 is a void that extends in the Y-axis directionover an entire region in which the plurality of nozzles N aredistributed. The aforementioned individual channel row 25 and theplurality of nozzles N are positioned between the first common liquidchamber R1 and the second common liquid chamber R2 as viewed in theZ-axis direction. In other words, the individual channel row 25 and theplurality of nozzles N are positioned between the first common liquidchamber R1 and the second common liquid chamber R2 in the X-axisdirection. Note that, in the following description, viewing in theZ-axis direction is also referred to as “plan view”.

Here, the first common liquid chamber R1 is coupled to an end E1 of eachof the individual channels P in direction X2. The first common liquidchamber R1 accumulates the ink to be supplied to each of the individualchannels P. On the other hand, the second common liquid chamber R2 iscoupled to an end E2 of each of the individual channels P in directionX1. The second common liquid chamber R2 accumulates the ink to bedischarged from each of the individual channels P without being ejected.

The circulation mechanism 26 is coupled to the first common liquidchamber R1 and the second common liquid chamber R2. The circulationmechanism 26 is a mechanism that causes the ink to be supplied to thefirst common liquid chamber R1 and collects the ink, which is dischargedfrom the second common liquid chamber R2, to supply the ink again to thefirst common liquid chamber R1. The circulation mechanism 26 includes afirst supply pump 261, a second supply pump 262, an accumulationcontainer 263, a collection channel 264, and a supply channel 265.

The first supply pump 261 is a pump that supplies the ink accumulated inthe liquid container 12 to the accumulation container 263. Theaccumulation container 263 is a temporary storage tank that temporarilystores the ink supplied from the liquid container 12. The collectionchannel 264 is a channel that enables the second common liquid chamberR2 and the accumulation container 263 to communicate with each other andthat collects, in the accumulation container 263, the ink from thesecond common liquid chamber R2. The ink accumulated in the liquidcontainer 12 is supplied from the first supply pump 261 to theaccumulation container 263, and the ink discharged from the respectiveindividual channels P to the second common liquid chamber R2 isadditionally supplied to the accumulation container 263 via thecollection channel 264. The second supply pump 262 is a pump thatdischarges the ink accumulated in the accumulation container 263. Thesupply channel 265 is a channel which enables the first common liquidchamber R1 and the accumulation container 263 to communicate with eachother and through which the ink from the accumulation container 263 issupplied to the first common liquid chamber R1.

A3: Specific Structure of Liquid Ejecting Head

FIG. 3 is a sectional view along line III-III in FIG. 2 . FIG. 3illustrates a sectional surface of the liquid ejecting head 24, which istaken along a plane parallel to the X-axis and the Z-axis of theindividual channel P. As illustrated in FIG. 3 , the liquid ejectinghead 24 includes a channel structure 30, a plurality of piezoelectricelements 41, a housing 42, a protection substrate 43, and a wiringsubstrate 44.

In the channel structure 30, the first common liquid chamber R1, thesecond common liquid chamber R2, the plurality of individual channels P,and the plurality of nozzles N described above are provided.Specifically, the channel structure 30 is a structure in which a nozzlesubstrate 31, a communication plate 33, a pressure chamber substrate 34,and a vibrating plate 35 are layered in this order in direction Z1.Members of the nozzle substrate 31, the communication plate 33, thepressure chamber substrate 34, and the vibrating plate 35 extend in theY-axis direction and are each manufactured such that, for example, asilicon monocrystalline substrate is processed by using a semiconductorprocessing technique. The members are bonded to each other with anadhesive or the like. Note that another layer or substrate such as anadhesive layer may be appropriately interposed between two adjacentmembers among the plurality of members that constitute the channelstructure 30.

The plurality of nozzles N are provided in the nozzle substrate 31. Theplurality of nozzles N are through holes that penetrate through thenozzle substrate 31 and that enable the ink to pass therethrough.

In the communication plate 33, a portion of the first common liquidchamber R1, a portion of the second common liquid chamber R2, and aportion other than the pressure chamber Ca and the pressure chamber Cbin each of the plurality of individual channels P are provided. Here,the individual channels P each include a first communication channelNa1, a second communication channel Na2, a first branch channel B1, anda second branch channel B2, a supply channel Ra1, and a dischargechannel Ra2 in addition to the pressure chamber Ca, the pressure chamberCb, and the nozzle channel Nf described above. Among these, the nozzlechannel Nf, the first communication channel Na1, the secondcommunication channel Na2, the first branch channel B1, and the secondbranch channel B2, the supply channel Ra1, and the discharge channel Ra2are provided in the communication plate 33.

The portion of the first common liquid chamber R1 and the portion of thesecond common liquid chamber R2 are voids penetrating through thecommunication plate 33. On the surface facing direction Z2 of thecommunication plate 33, a vibration absorber 361 and a vibrationabsorber 362 that close openings formed by the voids are disposed.

The vibration absorber 361 and the vibration absorber 362 are layermembers formed of an elastic material. The vibration absorber 361constitutes a portion of a wall surface of the first common liquidchamber R1 and absorbs a change in the pressure in the first commonliquid chamber R1. Similarly, the vibration absorber 362 constitutes aportion of a wall surface of the second common liquid chamber R2 andabsorbs a change in the pressure in the second common liquid chamber R2.

The nozzle channel Nf is a space in a groove provided on the surfacefacing direction Z2 of the communication plate 33. Here, the nozzlesubstrate 31 constitutes a portion of a wall surface of the nozzlechannel Nf.

The first communication channel Na1 and the second communication channelNa2 extend in the Z-axis direction and are spaces penetrating throughthe communication plate 33. The first communication channel Na1 enablesthe pressure chamber Ca and the nozzle channel Nf to communicate witheach other and guides the ink from the pressure chamber Ca to the nozzlechannel Nf. On the other hand, the second communication channel Na2enables the pressure chamber Cb and the nozzle channel Nf to communicatewith each other and guides the ink from the nozzle channel Nf to thepressure chamber Cb.

Each of the first branch channel B1 and the second branch channel B2 isa space formed by a groove provided on the surface facing direction Z1of the communication plate 33 and a hole penetrating through thecommunication plate 33 in the Z-axis direction. The first branch channelB1 enables the pressure chamber Ca and the nozzle channel Nf tocommunicate with each other through a path different from a path of thefirst communication channel Na1. The first branch channel B1 of thepresent embodiment has a first channel B1 a extending in in the X-axisdirection and a second channel B1 b extending in the Z-axis direction.On the other hand, the second branch channel B2 enables the pressurechamber Cb and the nozzle channel Nf to communicate with each otherthrough a path different from a path of the second communication channelNa2. The second branch channel B2 of the present embodiment has a thirdchannel B2 a extending in the X-axis direction and a fourth channel B2 bextending in the Z-axis direction. Note that the first branch channel B1and the second branch channel B2 will be described later in detail.

The supply channel Ra1 and the discharge channel Ra2 are spaces thatextend in the Z-axis direction and that penetrate through thecommunication plate 33. The supply channel Ra1 enables the first commonliquid chamber R1 and the pressure chamber Ca to communicate with eachother and is used to supply the ink from the first common liquid chamberR1 to the pressure chamber Ca. Here, one end of the supply channel Ra1is opened to the surface facing direction Z1 of the communication plate33. Meanwhile, the other end of the supply channel Ra1 is the end E1 onthe upstream of the individual channel P and is opened to a wall surfaceof the first common liquid chamber R1 in the communication plate 33. Onthe other hand, the discharge channel Ra2 enables the second commonliquid chamber R2 and the pressure chamber Cb to communicate with eachother and is used to discharge the ink from the pressure chamber Cb tothe second common liquid chamber R2. Here, one end of the dischargechannel Ra2 is opened to the surface facing direction Z1 of thecommunication plate 33. Meanwhile, the other end of the dischargechannel Ra2 is the end E2 on the downstream of the individual channel Pand is opened to a wall surface of the second common liquid chamber R2in the communication plate 33.

The pressure chambers Ca and the pressure chambers Cb of the pluralityof individual channels P are provided in the pressure chamber substrate34. The pressure chambers Ca and the pressure chambers Cb are voids thatpenetrate through the pressure chamber substrate 34 and that areprovided between the communication plate 33 and the vibrating plate 35.

The vibrating plate 35 is a plate member capable of elasticallyvibrating. The vibrating plate 35 is, for example, a layered body thatincludes a first layer made of silicon oxide (SiO₂) and a second layermade of zirconium oxide (ZrO₂). Here, another layer made of metal oxideor the like may be interposed between the first layer and the secondlayer. Note that a portion or entirety of the vibrating plate 35 may beformed to be integrated with the pressure chamber substrate 34 by thesame material. For example, the vibrating plate 35 and the pressurechamber substrate 34 are able to be integrally formed by a plate memberof a given thickness, from which some region corresponding to a pressurechamber C in the thickness direction is selectively removed. Moreover,the vibrating plate 35 may be formed by a single material layer.

The plurality of piezoelectric elements 41 corresponding to differentpressure chambers C are disposed on the surface facing direction Z1 ofthe vibrating plate 35. Here, a piezoelectric element 41 correspondingto each of the pressure chambers Ca is an example of a firstenergy-generating element. A piezoelectric element 41 corresponding toeach of the pressure chambers Cb is an example of a secondenergy-generating element. The piezoelectric elements 41 correspondingto the respective pressure chambers C overlap the pressure chambers C inplan view. Each of the piezoelectric elements 41 is constituted, forexample, by stacking a first electrode and a second electrode that faceeach other with a piezoelectric layer disposed between both theelectrodes. Each of the piezoelectric elements 41 changes the pressureof the ink in the pressure chamber C to thereby eject the ink in thepressure chamber C from the nozzle N. Upon supply of a driving voltage,the piezoelectric element 41 causes the piezoelectric element 41 todeform and thereby causes the vibrating plate 35 to vibrate. When thepressure chamber C expands and contracts upon the vibration, thepressure of the ink in the pressure chamber C changes.

The housing 42 is a case for accumulating the ink. In the housing 42, aspace that constitutes a remaining portion of the first common liquidchamber R1 other than a region provided in the communication plate 33and a space that constitutes a remaining portion of the second commonliquid chamber R2 other than a region provided in the communicationplate 33 are provided. A supply port 421 and a discharge port 422 areprovided in the housing 42. The supply port 421 is a pipeline, whichcommunicates with the first common liquid chamber R1, and is coupled tothe supply channel 265 of the circulation mechanism 26. Therefore, theink discharged from the second supply pump 262 to the supply channel 265is supplied to the first common liquid chamber R1 via the supply port421. On the other hand, the discharge port 422 is a pipeline, whichcommunicates with the second common liquid chamber R2, and is coupled tothe collection channel 264 of the circulation mechanism 26. Therefore,the ink in the second common liquid chamber R2 is discharged to thecollection channel 264 via the discharge port 422.

The protection substrate 43 is a plate member disposed on the surfacefacing direction Z1 of the vibrating plate 35, protects the plurality ofpiezoelectric elements 41, and reinforces the mechanical strength of thevibrating plate 35. Here, the plurality of piezoelectric elements 41 arehoused between the protection substrate 43 and the vibrating plate 35.

The wiring substrate 44 is mounted on the surface facing direction Z1 ofthe vibrating plate 35 and is a mounting component for electricallycoupling the control unit 21 and the liquid ejecting head 24. Forexample, a flexible wiring substrate 44, such as an FPC (flexibleprinted circuit) or FFC (flexible flat cable), is preferably used. Adrive circuit 45 for supplying a driving voltage to each of thepiezoelectric elements 41 is mounted on the wiring substrate 44.

In the liquid ejecting head 24 configured as described above, upon theoperation of the circulation mechanism 26 described above, the ink flowsin the first common liquid chamber R1, the supply channel Ra1, thepressure chamber Ca, the first communication channel Na1, the nozzlechannel Nf, the second communication channel Na2, the pressure chamberCb, the discharge channel Ra2, and the second common liquid chamber R2in this order. Here, a portion of the ink flowing from the pressurechamber Ca to the pressure chamber Cb passes through the firstcommunication channel Na1, the nozzle channel Nf, and the secondcommunication channel Na2 in this order and the rest of the inkappropriately passes through at least one of the first branch channel B1and the second branch channel B2. In the example illustrated in FIG. 3 ,a portion of the ink flowing from the pressure chamber Ca to thepressure chamber Cb may pass through the first branch channel B1 and thesecond branch channel B2 without passing through the nozzle channel Nf.

When piezoelectric elements 41 corresponding to both the pressurechamber Ca and the pressure chamber Cb are driven at the same time uponapplication of a driving voltage from the drive circuit 45, the pressureof the pressure chamber Ca and the pressure chamber Cb changes, and theink is ejected from the nozzle N in response to the change in pressure.Note that any operation period or any operation timing may be set as anoperation period or an operation timing of the circulation mechanism 26,and the operation period or the operation timing may be freely set so asto overlap a period or a timing of ejection of the ink from the nozzleN.

By causing the ink used for the liquid ejecting head 24 to circulate asdescribed above, it is possible to suppress an increase in viscosity andprecipitation of components of the ink near the nozzle N. Therefore, itis possible to prevent a deterioration in ejection characteristics suchas the ejection amount or ejection velocity of the ink in the liquidejecting head 24. As a result, it is possible to achieve stable ejectioncharacteristics of the ink in the liquid ejecting head 24 for a longtime period.

A4: Details of First Branch Channel and Second Branch Channel

FIG. 4 is an enlarged sectional view illustrating a portion of theliquid ejecting head 24 illustrated in FIG. 3 . In FIG. 4 , an ink flowpath from each of the pressure chamber Ca and the pressure chamber Cb tothe nozzle N is indicated by the thick broken line.

As described above, the nozzle channel Nf is the space in the grooveprovided on the surface facing direction Z2 of the communication plate33. Here, wall surfaces of the nozzle channel Nf include a wall surfaceF3 formed by the surface facing direction Z2 of the communication plate33 and a wall surface F4 formed by the surface facing direction Z1 ofthe nozzle substrate 31. The wall surface F3 is an example of a thirdwall surface. The wall surface F4 is an example of a fourth wallsurface.

The nozzle channel Nf extends in the X-axis direction, and the nozzle Nis provided in the middle of the nozzle channel Nf. In the exampleillustrated in FIG. 4 , the nozzle N is provided in the center of thenozzle channel Nf in the X-axis direction. The pressure chamber Cacommunicates with an end of the nozzle channel Nf in direction X2 viathe first communication channel Na1. Therefore, the pressure of thepressure chamber Ca is transferred to the nozzle N via the firstcommunication channel Na1 and the nozzle channel Nf. On the other hand,the pressure chamber Cb communicates with an end of the nozzle channelNf in direction X1 via the second communication channel Na2. Therefore,the pressure of the pressure chamber Cb is transferred to the nozzle Nvia the second communication channel Na2 and the nozzle channel Nf.

Here, since the nozzle N is not positioned directly below the pressurechamber Ca but is provided in the middle of the nozzle channel Nf,channel resistance of a channel extending from the pressure chamber Cato the nozzle N via the first communication channel Na1 tends to behigh.

Specifically, as described above, while the first communication channelNa1 extends in the Z-axis direction, the nozzle channel Nf extends inthe X-axis direction. Therefore, the first communication channel Na1 andthe nozzle channel Nf are orthogonal to each other. Accordingly, in thechannel extending from the pressure chamber Ca to the nozzle N via thefirst communication channel Na1, a pressure loss caused by frictionbetween the ink and a wall surface increases in accordance with adimension of the channel. Further, a pressure loss due to a vortex ofthe ink in a portion where the first communication channel Na1 and thenozzle channel Nf are coupled may be caused in some cases. As a result,channel resistance of the channel tends to be high.

By increasing sectional areas of the first communication channel Na1 andthe nozzle channel Nf, the channel resistance of the channel extendingfrom the pressure chamber Ca to the nozzle N via the first communicationchannel Na1 is able to be reduced. However, this makes a partition wall,which separates two first communication channels Na1 adjacent to eachother in the Y-axis direction, readily warped, and structural crosstalkmay be caused by warping of the partition wall.

Thus, the liquid ejecting head 24 includes, as the channel extendingfrom the pressure chamber Ca to the nozzle channel Nf, the first branchchannel B1 in addition to the first communication channel Na1. For asimilar reason, the liquid ejecting head 24 includes, as a channelextending from the pressure chamber Cb to the nozzle channel Nf, thesecond branch channel B2 in addition to the second communication channelNa2.

A partition wall 331 separates the first branch channel B1 and the firstcommunication channel Na1, and the first branch channel B1 is a channeldifferent from the first communication channel Na1. As described above,the first branch channel B1 has the first channel B1 a extending in theX-axis direction and the second channel B1 b extending in the Z-axisdirection. Similarly, a partition wall 332 separates the second branchchannel B2 and the second communication channel Na2, and the secondbranch channel B2 is a channel different from the second communicationchannel Na2. As described above, the second branch channel B2 has thethird channel B2 a extending in the X-axis direction and the fourthchannel B2 b extending in the Z-axis direction.

Here, the first branch channel B1 and the second branch channel B2 aresimilar in the configuration except that they are configuredsymmetrically in the X-axis direction. Thus, the first channel B1 a andthe third channel B2 a are configured symmetrically in the X-axisdirection. Moreover, the second channel B1 b and the fourth channel B2 bare configured symmetrically in the X-axis direction.

The first branch channel B1 will be representatively described below,and description for the second branch channel B2 will be omitted asappropriate. Note that the first branch channel B1 and the second branchchannel B2 may be configured asymmetrically in the X-axis direction.Note that, when the first branch channel B1 and the second branchchannel B2 are configured symmetrically in the X-axis direction, thereis an advantage that the liquid ejecting head 24 is easily designed.

The first channel B1 a is a space formed by a groove provided on thesurface facing direction Z1 of the communication plate 33. Here, wallsurfaces of the first channel B1 a include a wall surface F1 formed bythe surface facing direction Z2 of the pressure chamber substrate 34 anda wall surface F2 formed by the surface facing direction Z1 of thecommunication plate 33. The wall surface F1 is an example of a firstwall surface. The wall surface F2 is an example of a second wallsurface. An end of the aforementioned first channel B1 a in direction X2communicates with the pressure chamber Ca. On the other hand, an end ofthe first channel B1 a in direction X1 communicates with the secondchannel B1 b.

The second channel B1 b is a space formed by a hole penetrating throughthe communication plate 33 in the Z-axis direction. An end of the secondchannel B1 b in direction Z1 communicates with the first channel B1 a.On the other hand, an end of the second channel B1 b in direction Z2communicates with the nozzle channel Nf. Here, the second channel B1 bis positioned so as to overlap the nozzle N as viewed in the Z-axisdirection. Therefore, the pressure of the second channel B1 b is able tobe directly transferred to the nozzle N.

In the present embodiment, the second channel B1 b is shared with thefourth channel B2 b of the second branch channel B2. That is, the secondchannel B1 b and the fourth channel B2 b constitute one channelextending in the Z-axis direction. Thus, both the second channel B1 band the fourth channel B2 b are able to be arranged at a position wherethey overlap the nozzle N as viewed in the Z-axis direction.

Moreover, in the present embodiment, a dimension of a channel extendingfrom the pressure chamber Ca to the nozzle N via the first branchchannel B1 is substantially equal to a dimension of the channelextending from the pressure chamber Ca to the nozzle N via the firstcommunication channel Na1.

In the first branch channel B1 described above, channel resistance ofthe channel extending from the pressure chamber Ca to the nozzle N viathe first branch channel B1 is desired to be approximately the same aschannel resistance of the channel extending from the pressure chamber Cato the nozzle N via the first communication channel Na1 to transfer thepressure of the pressure chamber Ca via both the first communicationchannel Nal and the first branch channel B1 as efficiently as possible.

From the foregoing viewpoint, the sectional area of the first channel B1a is desirably equal to the sectional area of the nozzle channel Nf.Thus, when the first channel B1 a width in the Y-axis direction and thenozzle channel Nf width in the Y-axis direction are equal to each other,width Wb1 of the first channel B1 a in the Z-axis direction and width Wfof the nozzle channel Nf in the Z-axis direction are desirably equal toeach other.

Moreover, in the present embodiment, since the second channel B1 b isshared with the fourth channel B2 b of the second branch channel B2 asdescribed above, the sectional area of the second channel B1 b isdesirably larger than the sectional area of the first communicationchannel Na1 such that channel resistance of the second channel B1 b andchannel resistance of the first communication channel Na1 are equal toeach other. Thus, when the second channel B1 b width in the Y-axisdirection and the first communication channel Na1 width in the Y-axisdirection are equal to each other, width Wb2 of the second channel B1 bin the X-axis direction is desirably wider than width Wal of the firstcommunication channel Na1 in the X-axis direction. Note that the secondchannel B1 b width in the Y-axis direction and the first communicationchannel Na1 width in the Y-axis direction may differ from each othersuch that the channel resistance of the second channel B1 b and thechannel resistance of the first communication channel Nal are equal toeach other.

The liquid ejecting head 24 described above includes the pressurechamber Ca as an example of the first pressure chamber, the pressurechamber Cb as an example of the second pressure chamber, the nozzlechannel Nf, the first communication channel Na1, the secondcommunication channel Na2, and the first branch channel B1 as describedabove.

The pressure chamber Ca and the pressure chamber Cb each apply pressureto the ink that is an example of a liquid. The nozzle channel Nf extendsin the X-axis direction as an example of the first axis and is providedwith the nozzle N that ejects the ink. The first communication channelNa1 extends in the Z-axis direction as an example of the second axiscrossing the first axis and enables the pressure chamber Ca and thenozzle channel Nf to communicate with each other. The secondcommunication channel Nat extends in the Z-axis direction and enablesthe pressure chamber Cb and the nozzle channel Nf to communicate witheach other. The first branch channel B1 has a portion extending in theX-axis direction and enables the pressure chamber Ca and the nozzlechannel Nf to communicate with each other through a path different froma path of the first communication channel Na1.

In the liquid ejecting head 24 described above, since each of the firstcommunication channel Na1 and the first branch channel B1 enables thepressure chamber Ca and the nozzle channel Nf to communicate with eachother, it is possible to reduce the channel resistance of the channelextending from the pressure chamber Ca to the nozzle channel Nf comparedwith the configuration in which no first branch channel B1 is provided.As a result, it is possible to efficiently transfer the pressure fromthe pressure chamber Ca to the nozzle N compared with the configurationin which no first branch channel B1 is provided.

Here, since the first branch channel B1 is a path different from thefirst communication channel Na1, even when the channel resistance of thechannel extending from the pressure chamber Ca to the nozzle channel Nfis reduced, the sectional area of each of the channels is able to bereduced compared with the configuration in which no first branch channelB1 is provided. Thus, even when a plurality of channels described aboveare arrayed in the Y-axis direction, it is possible to suppress warpingof a partition wall that separates the channels. As a result, it ispossible to reduce structural crosstalk caused by warping of thepartition wall between the channels.

Since the first branch channel B1 has the portion extending in theX-axis direction, it is possible to increase the aforementionedpartition wall in thickness compared with the configuration in which thefirst branch channel B1 does not have the portion. In addition, in theconfiguration in which the first branch channel B1 has the portion, evenwhen the nozzle N is provided in the middle of the nozzle channel Nfextending in the X-axis direction, a communication position of the firstbranch channel B1 and the nozzle channel Nf is readily close to thenozzle N compared with the configuration in which the first branchchannel B1 does not have the portion. Therefore, when the communicationposition becomes close to the nozzle N, it is possible to efficientlytransfer the pressure from the pressure chamber Ca to the nozzle N viathe first branch channel B1.

In the present embodiment, as described above, the first branch channelB1 has the first channel B1 a and the second channel B1 b. The firstchannel B1 a extends in the X-axis direction and communicates with thepressure chamber Ca. On the other hand, the second channel B1 b extendsin the Z-axis direction and enables the first channel B1 a and thenozzle channel Nf to communicate with each other. Such a first branchchannel B1 having the first channel B1 a and the second channel B1 benables the pressure chamber Ca and the nozzle channel Nf to communicatewith each other and enables the partition wall 331 to be increased inthickness in the X-axis direction in accordance with a dimension of thefirst channel B1 a.

As described above, the pressure chamber Ca and the nozzle channel Nfeach extend in the X-axis direction. Here, the first communicationchannel Na1 enables an end of the pressure chamber Ca in direction X1that is one direction extending in the X-axis direction and an end ofthe nozzle channel Nf in direction X2 that is the other directionextending in the X-axis direction to communicate with each other.Therefore, it is possible to efficiently transfer the pressure from thepressure chamber Ca to the nozzle N via the first communication channelNa1 compared with the configuration in which the first communicationchannel Na1 communicates with an intermediate portion of the pressurechamber Ca or communicates with an intermediate portion of the nozzlechannel Nf in the X-axis direction.

As described above, the first branch channel B1 communicates with thenozzle channel Nf at a position closer than the first communicationchannel Na1 to the nozzle N. Therefore, it is possible to efficientlytransfer the pressure from the pressure chamber Ca to the nozzle N viathe first branch channel B1 compared with the configuration in which thefirst branch channel B1 communicates with the nozzle channel Nf at aposition farther than the first communication channel Na1 from thenozzle N.

In the liquid ejecting head 24, as described above, the channelsregarding the pressure chamber Cb are configured similarly to thechannels regarding the pressure chamber Ca. That is, the liquid ejectinghead 24 further includes the second branch channel B2. The second branchchannel B2 has a portion extending in the X-axis direction and enablesthe pressure chamber Cb and the nozzle channel Nf to communicate witheach other through a path different from a path of the secondcommunication channel Na2.

Therefore, similarly to the aforementioned channel extending from thepressure chamber Ca to the nozzle channel Nf, it is possible to reducechannel resistance of a channel extending from the pressure chamber Cbto the nozzle Nf and suppress warping of a partition wall that separateschannels compared with the configuration in which no second branchchannel B2 is provided. In addition, similarly to the pressure beingtransferred from the pressure chamber Ca to the nozzle N as describedabove, it is possible to efficiently transfer the pressure from thepressure chamber Cb to the nozzle N via the second branch channel B2.

Here, similarly to the first channel B1 a and the second channel B1 b ofthe first branch channel B1, the second branch channel B2 has the thirdchannel B2 a and the fourth channel B2 b as described above. In thepresent embodiment, the second channel B1 b and the fourth channel B2 bare shared. That is, the first branch channel B1 and the second branchchannel B2 respectively have the second channel B1 b and the fourthchannel B2 b as a shared portion extending in the Z-axis direction.Therefore, a communication position of the first branch channel B1 andthe nozzle channel Nf is able to match a communication position of thesecond branch channel B2 and the nozzle channel Nf. As a result, boththe communication positions are able to be close to the nozzle N.

As described above, the liquid ejecting head 24 further includes thepressure chamber substrate 34, the communication plate 33, and thenozzle substrate 31. The pressure chamber substrate 34 is provided withthe pressure chamber Ca and the pressure chamber Cb. The communicationplate 33 is provided with the nozzle channel Nf, the first communicationchannel Na1, the second communication channel Na2, and the first branchchannel B1. The nozzle substrate 31 is provided with the nozzle N. Inthe liquid ejecting head 24 constituted by using such a plurality ofsubstrates, by processing and bonding the plurality of substrates, therespective channels and the respective pressure chambers C that areexcellent in dimensional accuracy are able to be formed with good yield.

Here, wall surfaces of the first branch channel B1 include the wallsurface F1 as an example of the first wall surface and the wall surfaceF2 as an example of the second wall surface. The wall surface F1 isconstituted by the pressure chamber substrate 34. The wall surface F2 ispositioned opposite to the wall surface F1 in the Z-axis direction andis constituted by the communication plate 33. In this manner, byconstituting the wall surfaces of the first branch channel B1 by usingthe communication plate 33 and the pressure chamber substrate 34, aportion extending in the X-axis direction is able to be easily formed inthe first branch channel B1 by using, for example, a groove formed onthe wall surface F1 or the wall surface F2.

The nozzle channel Nf has the wall surface F3 as an example of the thirdwall surface and the wall surface F4 as an example of the fourth wallsurface. The wall surface F3 is constituted by the communication plate33. The wall surface F4 is positioned opposite to the wall surface F3 inthe Z-axis direction and is constituted by the nozzle substrate 31. Inthis manner, by constituting the wall surfaces of the nozzle channel Nfby using the nozzle substrate 31 and the communication plate 33, thenozzle channel Nf extending in the X-axis direction is able to be easilyformed by using, for example, a groove formed on the wall surface F3 orthe wall surface F4.

As described above, the liquid ejecting head 24 further includes thesupply channel Ra1 and the discharge channel Ra2. The supply channel Ra1communicates with the pressure chamber Ca to supply the ink to thepressure chamber Ca. The discharge channel Ra2 communicates with thepressure chamber Cb to discharge the ink from the pressure chamber Cb.The supply channel Ra1 and the discharge channel Ra2 enable a reductionin ink staying in the channel between the supply channel Ra1 and thedischarge channel Ra2. Thus, it is possible to suppress an increase inviscosity and precipitation of components of the ink near the nozzle N.As a result, it is possible to prevent a deterioration in ejectioncharacteristics such as the ejection amount or ejection velocity of theink in the liquid ejecting head 24.

Here, supply of the ink from the supply channel Ra1 to the pressurechamber Ca and discharge of the ink from the pressure chamber Cb to thedischarge channel Ra2 are performed by the operation of the circulationmechanism 26. Note that, in the aforementioned coupling form of thecirculation mechanism 26 and the liquid ejecting head 24, the supplyingside and the discharging side may be reversed. In this case, the supplychannel Ra1 functions as a discharge channel through which the ink isdischarged from the pressure chamber Ca, and the discharge channel Ra2functions as a supply channel through which the ink is supplied to thepressure chamber Cb.

As described above, the first branch channel B1 has the second channelB1 b as a portion extending in the Z-axis direction. Here, the area ofthe second channel B1 b as viewed in the Z-axis direction is desirablyequal to the area of the first communication channel Na1 as viewed inthe Z-axis direction. When the areas are equal to each other, thechannel resistance of the first communication channel Na1 is able to beequal to channel resistance of the first branch channel B1. As a result,the ink is able to flow smoothly in each of the first communicationchannel Na1 and the first branch channel B1 compared with theconfiguration in which the channel resistances differ from each other.Note that the term “equal” herein includes not only a case of beingstrictly equal but also a case of being equal with a difference in arange of manufacturing error or the like.

As described above, the liquid ejecting head 24 further includes theplurality of piezoelectric elements 41 and the drive circuit 45. Here,of the plurality of piezoelectric elements 41, a piezoelectric element41 that, upon application of a driving voltage, generates energy forapplying the pressure to the ink of the pressure chamber Ca is anexample of the first energy-generating element, and a piezoelectricelement 41 that, upon application of a driving voltage, generates energyfor applying the pressure to the ink of the pressure chamber Cb is anexample of the second energy-generating element. The drive circuit 45applies a driving voltage to both the piezoelectric elements 41.Therefore, it is possible to simplify the configuration of the liquidejecting head 24 compared with the configuration in which separate drivecircuits are used for the piezoelectric element 41 for the pressurechamber Ca and the piezoelectric element 41 for the pressure chamber Cb.

Here, the drive circuit 45 is positioned between the piezoelectricelement 41 for the pressure chamber Ca and the piezoelectric element 41for the pressure chamber Cb in the X-axis direction. Therefore, comparedwith the configuration in which the drive circuit 45 is at a differentposition, supply paths of the driving voltage from the drive circuit 45to both the piezoelectric elements 41 are able to be shortened.Moreover, according to the present configuration, the dimension of thenozzle channel Nf in the X-axis direction is elongated to ensure a spacein which the drive circuit 45 is disposed. Thus, when such aconfiguration is adopted, it is particularly effective to reduce thechannel resistance of the channel extending from the pressure chamber Cato the nozzle channel Nf and the channel resistance of the channelextending from the pressure chamber Cb to the nozzle channel Nf.

As described above, the aforementioned liquid ejecting apparatus 100includes the liquid ejecting head 24 and the control unit 21 that is anexample of the control section. The control unit 21 controls the inkejection operation of the liquid ejecting head 24. According to theaforementioned liquid ejecting apparatus 100, the liquid ejecting head24 has excellent ejection characteristics as described above, imagequality is able to be improved.

B: Second Embodiment

A second embodiment of the disclosure will be described below. In anaspect exemplified below, an element having an effect and a functionthat are similar to those of the first embodiment will be given areference numeral used in the description of the first embodiment, anddetailed description thereof will be omitted as appropriate.

FIG. 5 is an enlarged sectional view illustrating a portion of a liquidejecting head 24A according to the second embodiment. The liquidejecting head 24A is similar to the liquid ejecting head 24 of the firstembodiment described above except that a channel structure 30A isprovided instead of the channel structure 30. The channel structure 30Ais similar to the channel structure 30 except that a communication plate33A is provided instead of the communication plate 33. The communicationplate 33A is similar to the communication plate 33 except that apartition wall 333 is provided. Note that, in the following description,the matter regarding the first branch channel B1 will berepresentatively described, and the matter regarding the second branchchannel B2 is similar to that of the first branch channel B1, and thusdescription thereof will be omitted as appropriate.

The partition wall 333 is a member that separates the first branchchannel B1 and the second branch channel B2. In the example illustratedin FIG. 5 , the partition wall 333 extends from the pressure chambersubstrate 34 in direction Z2. A gap that is approximately equal to widthWf of the nozzle channel Nf in the Z-axis direction is formed betweenthe partition wall 333 and the nozzle substrate 31.

As described above, the liquid ejecting head 24A of the presentembodiment includes the partition wall 333 as an example of a firstpartition wall and the partition wall 331 as an example of a secondpartition wall. The partition wall 333 separates the first branchchannel B1 and the second branch channel B2. The partition wall 331separates the first communication channel Na1 and the first branchchannel B1.

Here, thickness t1 of the partition wall 333 in the X-axis direction issmaller than thickness t2 of the partition wall 331 in the X-axisdirection. Therefore, a distance between a communication position of thefirst branch channel B1 and the nozzle channel Nf and a communicationposition of the second branch channel B2 and the nozzle channel Nf isable to be shortened compared with the configuration in which thicknesst1 of the partition wall 333 is greater than thickness t2 of thepartition wall 331. As a result, the respective communication positionsare able to be close to the nozzle N. Moreover, compared with theconfiguration in which no partition wall 333 is provided, in theconfiguration in which the partition wall 333 is provided, the amount ofthe ink flowing between the first branch channel B1 and the secondbranch channel B2 is reduced, thus making it possible to reduce apressure loss due to a turbulent flow or the like between the channels.

From the viewpoint of making the dimension of the channel extending fromthe pressure chamber Ca to the nozzle N as short as possible, thicknesst1 of the partition wall 333 in the X-axis direction is desirablysmaller than width Wal of the first communication channel Na1 in theX-axis direction. Note that thickness t1 is fixed in the exampleillustrated in FIG. 5 , but thickness t1 may be unfixed.

Moreover, similarly to the first embodiment described above, the firstbranch channel B1 has the second channel B1 b as a portion extending inthe Z-axis direction. Here, the area of the second channel B1 b asviewed in the Z-axis direction is desirably equal to the area of thefirst communication channel Na1 as viewed in the Z-axis direction. Whenthe areas are equal to each other, the channel resistance of the firstcommunication channel Na1 is able to be equal to the channel resistanceof the first branch channel B1. As a result, the ink is able to flowsmoothly in each of the first communication channel Na1 and the firstbranch channel B1 compared with the configuration in which the channelresistances differ from each other.

The second embodiment described above also enables efficient transfer ofthe pressure from the pressure chamber Ca to the nozzle N whileachieving desired ejection characteristics.

Moreover, in the second embodiment, the ink passing through the firstbranch channel B1 always passes through immediately above the nozzle N.Thus, the amount of the ink passing through immediately above the nozzleN increases compared with the first embodiment. As a result, it ispossible to further suppress an increase in viscosity near the nozzle Ndue to, for example, the ink being evaporated from the nozzle N.

C: Third Embodiment

A third embodiment of the disclosure will be described below. In anaspect exemplified below, an element having an effect and a functionthat are similar to those of the first embodiment will be given areference numeral used in the description of the first embodiment, anddetailed description thereof will be omitted as appropriate.

FIG. 6 is an enlarged sectional view illustrating a portion of a liquidejecting head 24B according to the third embodiment. The liquid ejectinghead 24B is similar to the liquid ejecting head 24 of the firstembodiment described above except that a channel structure 30B isprovided instead of the channel structure 30. The channel structure 30Bis similar to the channel structure 30 except that a communication plate33B is provided instead of the communication plate 33. The communicationplate 33B is similar to the communication plate 33A of the secondembodiment described above except that a partition wall 333B is providedinstead of the partition wall 333. Note that, in the followingdescription, the matter regarding the first branch channel B1 will berepresentatively described, and the matter regarding the second branchchannel B2 is similar to that of the first branch channel B1, and thusdescription thereof will be omitted as appropriate.

The partition wall 333B is similar to the partition wall 333 of thesecond embodiment described above except that a third communicationchannel B3 is provided. The third communication channel B3 is a channelpassing through the partition wall 333B and enables the first branchchannel B1 and the second branch channel B2 to communicate with eachother. In the example illustrated in FIG. 6 , the third communicationchannel B3 is formed by a groove provided on the surface facingdirection Z1 of the partition wall 333B. Note that the thirdcommunication channel B3 may be formed by a through hole penetratingthrough the partition wall 333B.

As described above, the liquid ejecting head 24B further includes thethird communication channel B3 that enables the first branch channel B1and the second branch channel B2 to communicate with each other througha path different from a path of the nozzle channel Nf. Therefore, airbubbles are able to flow from one of the first branch channel B1 and thesecond branch channel B2 to the other channel via the thirdcommunication channel B3. As a result, it is possible to reduce airbubbles staying in the first branch channel B1 and the second branchchannel B2. Note that the flow of air bubbles through the thirdcommunication channel B3 is performed upon mainly the operation of thecirculation mechanism 26 described above.

Here, from the viewpoint of efficiently transferring pressure from thefirst channel B1 a to the second channel B1 b, the third communicationchannel B3 width in the Z-axis direction is narrower than width Wbi ofthe first channel B1 a.

The third embodiment described above also enables efficient transfer ofpressure from the pressure chamber Ca to the nozzle N while achievingdesired ejection characteristics.

R: Fourth Embodiment

A fourth embodiment of the disclosure will be described below. In anaspect exemplified below, an element having an effect and a functionthat are similar to those of the first embodiment will be given areference numeral used in the description of the first embodiment, anddetailed description thereof will be omitted as appropriate.

FIG. 7 is an enlarged sectional view illustrating a portion of a liquidejecting head 24C according to the fourth embodiment. The liquidejecting head 24C is similar to the liquid ejecting head 24 of the firstembodiment described above except that a channel structure 30C isprovided instead of the channel structure 30. The channel structure 30Cis similar to the channel structure 30 except that a communication plate33C is provided instead of the communication plate 33. The communicationplate 33C is similar to the communication plate 33 except for adifference in the configuration of the first branch channel B1 and thesecond branch channel B2. Note that, in the following description, thematter regarding the first branch channel B1 will be representativelydescribed, and the matter regarding the second branch channel B2 issimilar to that of the first branch channel B1, and thus descriptionthereof will be omitted as appropriate.

The first branch channel B1 of the present embodiment has a portionextending from the pressure chamber Ca in direction Z2, and a partitionwall 335 separates the first branch channel B1 and the firstcommunication channel Na1. The first branch channel B1 of the presentembodiment has a first channel B1 c extending in the Z-axis directionand a second channel B1 d extending in the X-axis direction.

Similarly, the second branch channel B2 of the present embodiment has aportion extending from the pressure chamber Cb in direction Z2, and apartition wall 336 separates the second branch channel B2 and the secondcommunication channel Na2. The second branch channel B2 of the presentembodiment has a third channel B2 c extending in the Z-axis directionand a fourth channel B2 d extending in the X-axis direction.

Here, the first branch channel B1 and the second branch channel B2 aresimilar in the configuration except that they are configuredsymmetrically in the X-axis direction. Thus, the first channel B1 c andthe third channel B2 c are configured symmetrically in the X-axisdirection. Moreover, the second channel B1 d and the fourth channel B2 dare configured symmetrically in the X-axis direction.

The first branch channel B1 will be representatively described below,and description for the second branch channel B2 will be omitted asappropriate. Note that the first branch channel B1 and the second branchchannel B2 may be configured asymmetrically in the X-axis direction.

The first channel B1 c is a space formed by a hole penetrating throughthe communication plate 33C in the Z-axis direction. An end of theaforementioned first channel B1 c in direction Z1 communicates with thepressure chamber Ca. On the other hand, an end of the first channel B1 cin direction Z2 communicates with the second channel B1 d.

The second channel B1 d is a space formed by a groove provided on thesurface facing direction Z2 of the communication plate 33C. An end ofthe second channel B1 d in direction X2 communicates with the firstchannel B1 c. On the other hand, an end of the second channel B1 d indirection X1 communicates with the nozzle channel Nf. Here, the secondchannel B1 d is formed by extending the nozzle channel Nf, and it may besaid that the second channel B1 d constitutes a portion of the nozzlechannel Nf.

The fourth embodiment described above also enables efficient transfer ofpressure from the pressure chamber Ca to the nozzle N while achievingdesired ejection characteristics. According to the present embodiment,it is also possible to shorten dimensions of the portions extending inthe X-axis direction of the first branch channel B1 and the secondbranch channel B2. Thus, there is an advantage that channel resistancesof the channels are easily reduced.

E: Reference Example

A reference example will be described below. In an aspect exemplifiedbelow, an element having an effect and a function that are similar tothose of the first embodiment will be given a reference numeral used inthe description of the first embodiment, and detailed descriptionthereof will be omitted as appropriate.

E1: Channels of Liquid Ejecting Head

FIG. 8 is a schematic view of channels of a liquid ejecting head 24Daccording to the reference example. The liquid ejecting head 24D issimilar to the liquid ejecting head 24 of the first embodiment describedabove except that a plurality of individual channels Pa and a pluralityof individual channels Pb are provided instead of the plurality ofindividual channels P. That is, as illustrated in FIG. 8 , the liquidejecting head 24D includes the plurality of nozzles N, the plurality ofindividual channels Pa, the plurality of individual channels Pb, thefirst common liquid chamber R1, and the second common liquid chamber R2,and the circulation mechanism 26 is coupled to the liquid ejecting head24.

Specifically, the liquid ejecting head 24D has a surface facing themedium 11, and a plurality of nozzles Na and a plurality of nozzles Nbare provided on the surface as illustrated in FIG. 8 . The nozzles aresimilar to the nozzles N in the first embodiment described above in theconfiguration and eject the ink in direction Z2. Note that, in thefollowing description, when there is no particular necessity todistinguish between the nozzles Na and the nozzles Nb, they are simplyreferred to also as “nozzles N”.

The plurality of nozzles Na are arrayed in the Y-axis direction and aset of them constitutes a first nozzle row La. Similarly, the pluralityof nozzles Nb are arrayed in the Y-axis direction, and a set of themconstitutes a second nozzle row Lb.

The first nozzle row La and the second nozzle row Lb are arranged sideby side with a given gap therebetween in the X-axis direction. Here,although a pitch at which the nozzles Na are arrayed and a pitch atwhich the nozzles Nb are arrayed are equal to each other, a nozzle Naand a nozzle Nb that are closest to each other are arranged so as to beshifted from each other at the aforementioned pitch θ in the Y-axisdirection.

Each of the plurality of nozzles Na communicates with a correspondingone of the individual channels Pa. The plurality of individual channelsPa extend in the X-axis direction and communicate with different nozzlesNa. Similarly, each of the plurality of nozzles Nb communicates with acorresponding one of the individual channels Pb. The plurality ofindividual channels Pb extend in the X-axis direction and communicatewith different nozzles Nb. The individual channel Pa and the individualchannel Pb are alternately arrayed in the Y-axis direction, and a set ofthe plurality of individual channels Pa and the plurality of individualchannels Pb constitutes an individual channel row 25D.

The individual channel Pa is similar to the individual channel P of thefirst embodiment described above except that the pressure chamber Cb isomitted. Specifically, the individual channel Pa includes a firstportion Pa1 and a second portion Pa2. The first portion Pal of theindividual channel Pa is a channel between the upstream end E1 of theindividual channel Pa and the nozzle Na. The first portion Pa1 includesthe pressure chamber Ca. On the other hand, the second portion Pa2 ofthe individual channel Pa is a channel between the downstream end E2 ofthe individual channel Pa and the nozzle Na.

The individual channel Pb is similar to the individual channel P of thefirst embodiment described above except that the pressure chamber Ca isomitted. Specifically, the individual channel Pb includes a thirdportion Pb1 and a fourth portion Pb2. The third portion Pb1 of theindividual channel Pb is a channel between the upstream end E1 of theindividual channel Pb and the nozzle Nb. On the other hand, the fourthportion Pb2 of the individual channel Pb is a channel between thedownstream end E2 of the individual channel Pb and the nozzle Nb. Thefourth portion Pb2 includes the pressure chamber Cb.

The upstream end E1 of each of the individual channels Pa and theupstream end E1 of each of the individual channels Pb are coupled to thefirst common liquid chamber R1. On the other hand, the downstream end E2of each of the individual channels Pa and the downstream end E2 of eachof the individual channels Pb are coupled to the second common liquidchamber R2.

E2: Specific Structure of Liquid Ejecting Head

FIG. 9 is a sectional view along line IX-IX in FIG. 8 . FIG. 9illustrates a sectional surface of the liquid ejecting head 24D, whichis taken along a plane parallel to the X-axis and the Z-axis of theindividual channel Pa. FIG. 10 is a sectional view along line X-X inFIG. 8 . FIG. 10 illustrates a sectional surface of the liquid ejectinghead 24D, which is taken along a plane parallel to the X-axis and theZ-axis of the individual channel Pb.

As illustrated in FIGS. 9 and 10 , the liquid ejecting head 24D issimilar to the liquid ejecting head 24 of the first embodiment describedabove except that a lateral communication channel Cq1 is providedinstead of a portion of the pressure chamber Ca and that a lateralcommunication channel Cq2 is provided instead of a portion of thepressure chamber Cb.

As illustrated in FIGS. 9 and 10 , the liquid ejecting head 24D includesa channel structure 30D, the plurality of piezoelectric elements 41, thehousing 42, the protection substrate 43, and the wiring substrate 44.

The channel structure 30D includes the first common liquid chamber R1,the second common liquid chamber R2, the plurality of individualchannels Pa, the plurality of individual channels Pb, and the pluralityof nozzles N described above. Specifically, the channel structure 30D issimilar to the channel structure 30 of the first embodiment describedabove except that a nozzle substrate 31D, a communication plate 33D, anda pressure chamber substrate 34D are provided instead of the nozzlesubstrate 31, the communication plate 33, and the pressure chambersubstrate 34.

The nozzle substrate 31D is provided with the plurality of nozzles Naand the plurality of nozzles Nb. Here, the nozzle substrate 31D issimilar to the nozzle substrate 31 described above in the configurationexcept for a difference in arrangement of the nozzles Na and the nozzlesNb.

In the communication plate 33D, a portion of the first common liquidchamber R1, a portion of the second common liquid chamber R2, a portionother than the pressure chamber Ca in each of the plurality ofindividual channels Pa, and a portion other than the pressure chamber Cbin each of the plurality of individual channels Pb are provided.

As illustrated in FIG. 9 , each of the individual channels Pa has, inaddition to the pressure chamber Ca described above, a nozzle channelNfa, the lateral communication channel Cq1, the first communicationchannel Na1, the second communication channel Na2, a branch channel Ba,the supply channel Ra1, and the discharge channel Ra2. Among these, thenozzle channel Nfa, the lateral communication channel Cq1, the firstcommunication channel Na1, the second communication channel Na2, thebranch channel Ba, the supply channel Ra1, and the discharge channel Ra2are provided in the communication plate 33D.

The nozzle channel Nfa is a space in a groove provided on the surfacefacing direction Z2 of the communication plate 33D. Here, the nozzlesubstrate 31D constitutes a portion of a wall surface of the nozzlechannel Nfa. The nozzle channel Nfa is provided with the nozzle Na.

The first communication channel Na1 enables the pressure chamber Ca andthe nozzle channel Nfa to communicate with each other and guides the inkfrom the pressure chamber Ca to the nozzle channel Nfa. On the otherhand, the second communication channel Na2 enables the lateralcommunication channel Cq1 and the nozzle channel Nfa to communicate witheach other and guides the ink from the nozzle channel Nfa to the lateralcommunication channel Cq1.

The branch channel Ba enables the pressure chamber Ca and the nozzlechannel Nfa to communicate with each other through a path different froma path of the first communication channel Na1 and guides the ink fromthe pressure chamber Ca to the nozzle channel Nfa. Similarly to thefirst branch channel B1 of the first embodiment described above, thebranch channel Ba has the first channel B1 a extending in the X-axisdirection and the second channel B1 b extending in the Z-axis direction.

The lateral communication channel Cq1 is a space extending in the X-axisdirection. The lateral communication channel Cq1 enables the secondcommunication channel Na2 and the discharge channel Ra2 to communicatewith each other and guides the ink from the second communication channelNa2 to the discharge channel Ra2.

The supply channel Ra1 enables the first common liquid chamber R1 andthe pressure chamber Ca to communicate with each other and is used tosupply the ink from the first common liquid chamber R1 to the pressurechamber Ca. On the other hand, the discharge channel Ra2 enables thesecond common liquid chamber R2 and the lateral communication channelCq1 to communicate with each other and is used to discharge the ink fromthe lateral communication channel Cq1 to the second common liquidchamber R2.

On the other hand, each of the individual channels Pb and each of theindividual channels Pa described above are symmetrically configured inthe X-axis direction. Specifically, as illustrated in FIG. 10 , each ofthe individual channels Pb has, in addition to the pressure chamber Cbdescribed above, a nozzle channel Nfb, the lateral communication channelCq2, a third communication channel Nb1, a fourth communication channelNb2, a branch channel Bb, a supply channel Rb1, and a discharge channelRb2. Among these, the nozzle channel Nfb, the lateral communicationchannel Cq2, the third communication channel Nb1, the fourthcommunication channel Nb2, the branch channel Bb, the supply channelRb1, and the discharge channel Rb2 are provided in the communicationplate 33D.

The nozzle channel Nfb is a space in a groove provided on the surfacefacing direction Z2 of the communication plate 33D. Here, the nozzlesubstrate 31D constitutes a portion of a wall surface of the nozzlechannel Nfb. The nozzle channel Nfb is provided with the nozzle Nb.

The third communication channel Nb1 enables the lateral communicationchannel Cq2 and the nozzle channel Nfb to communicate with each otherand guides the ink from the lateral communication channel Cq2 to thenozzle channel Nfb. On the other hand, the fourth communication channelNb2 enables the pressure chamber Cb and the nozzle channel Nfb tocommunicate with each other and guides the ink from the nozzle channelNfb to the pressure chamber Cb.

The branch channel Bb enables the pressure chamber Cb and the nozzlechannel Nfb to communicate with each other through a path different froma path of the fourth communication channel Nb2 and guides the ink fromthe pressure chamber Cb to the nozzle channel Nfb. Similarly to thesecond branch channel B2 of the first embodiment described above, thebranch channel Bb has the third channel B2 a extending in the X-axisdirection and the fourth channel B2 b extending in the Z-axis direction.

The lateral communication channel Cq2 enables the supply channel Rb1 andthe third communication channel Nb1 to communicate with each other andguides the ink from the supply channel Rb1 to the third communicationchannel Nb1.

The supply channel Rb1 enables the first common liquid chamber R1 andthe lateral communication channel Cq2 to communicate with each other andis used to supply the ink from the first common liquid chamber R1 to thelateral communication channel Cq2. On the other hand, the dischargechannel Rb2 enables the second common liquid chamber R2 and the pressurechamber Cb to communicate with each other and is used to discharge theink from the pressure chamber Cb to the second common liquid chamber R2.

The pressure chamber substrate 34D is similar to the pressure chambersubstrate 34 of the first embodiment described above except for adifference in arrangement of the pressure chamber Ca and the pressurechamber Cb. Specifically, as illustrated in FIGS. 9 and 10 , thepressure chambers Ca in the plurality of individual channels Pa and thepressure chambers Cb in the plurality of individual channels Pb areprovided in the pressure chamber substrate 34D. Note that the pluralityof piezoelectric elements 41 are arranged so as to correspond toarrangement of the plurality of pressure chambers Ca and the pluralityof pressure chambers Cb provided in the pressure chamber substrate 34D.

The foregoing reference example is also able to achieve an effectsimilar to that of the first embodiment described above. In the liquidejecting head 24D of the present reference example, a channel of anindividual channel Pb overlaps neither a pressure chamber Ca nor alateral communication channel of an individual channel Pa that isadjacent to the individual channel Pb. Similarly, a channel of anindividual channel Pa overlaps neither a pressure chamber Cb nor alateral communication channel Cq2 of an individual channel Pb that isadjacent to the individual channel Pa as viewed in the Y-axis direction.Therefore, even when the pitch θ is reduced, crosstalk between theindividual channel Pa and the individual channel Pb that are adjacent toeach other is difficult to be caused compared with the embodimentsdescribed above. As a result, by increasing nozzle resolution in theZ-axis direction with a reduction in the pitch θ, image quality is ableto be improved.

F: Modified Examples

Each of the aspects exemplified above can be variously modified.Specific aspects of the modifications that can be applied to each of theaspects described above will be exemplified below. Any aspects selectedfrom the following examples can be combined with each other within thescope in which they do not conflict.

Modified Example 1

Although each of the aspects described above exemplifies theconfiguration in which the nozzle channel, the first communicationchannel, and the second communication channel are each formed so as tolinearly extend with a certain width, the configuration of thedisclosure is not limited thereto. For example, each of the channels mayhave a portion that is bent or curved in the middle of the channel ormay have a plurality of portions that differ in width. Similarly, thefirst channel or the second channel in the first branch channel may havea portion that is bent or curved in the middle of the channel or mayhave a plurality of portions that differ in width. Moreover, the thirdchannel or the fourth channel in the second branch channel may have aportion that is bent or curved in the middle of the channel or may havea plurality of portions that differ in width.

Modified Example 2

Although each of the aspects described above exemplifies theconfiguration in which the ink used for the liquid ejecting head iscirculated by the circulation mechanism, the configuration of thedisclosure is not limited thereto and may be a configuration in whichsuch a mechanism for circulation is not provided.

Modified Example 3

The energy-generating element that changes the pressure of the ink inthe pressure chamber C is not limited to the piezoelectric element 41exemplified in each of the aspects described above. For example, aheating element that generates air bubbles in the pressure chamber C byheating and thereby changes the pressure of the ink may be used as theenergy-generating element.

Modified Example 4

Although each of the aspects described above exemplifies the liquidejecting apparatus 100 of a serial type in which the transport body 231on which the liquid ejecting head 24 is mounted is reciprocated, thedisclosure is applicable to a liquid ejecting apparatus of a line typein which a plurality of nozzles N are distributed over the entire widthof the medium 11.

The liquid ejecting apparatus 100 exemplified in the aspects describedabove may be adopted for various apparatuses such as a facsimileapparatus and a copying machine in addition to equipment dedicated toprinting, and the use of the disclosure is not particularly limited.Needless to say, the liquid ejecting apparatus is not limited to beingused for printing. For example, a liquid ejecting apparatus that ejectsa solution of a color material is used as a manufacturing apparatus thatforms a color filter of a display apparatus such as a liquid crystaldisplay panel. Further, a liquid ejecting apparatus that ejects asolution of a conductive material is used as a manufacturing apparatusthat forms a wire and an electrode of a wiring substrate. In addition, aliquid ejecting apparatus that ejects an organic solution regarding aliving body is used as a manufacturing apparatus that manufactures abiochip, for example.

What is claimed is:
 1. A liquid ejecting head comprising: a firstpressure chamber that applies pressure to a liquid; a second pressurechamber that applies pressure to the liquid; a nozzle channel thatextends in a first direction and communicates with a nozzle that ejectsthe liquid; a first communication channel that extends in a seconddirection crossing the first direction and enables the first pressurechamber and the nozzle channel to communicate with each other; a secondcommunication channel that extends in the second direction and enablesthe second pressure chamber and the nozzle channel to communicate witheach other; and a first branch channel that has a portion extending inthe first direction and enables the first pressure chamber and thenozzle channel to communicate with each other through a path differentfrom a path of the first communication channel, wherein the firstpressure chamber, the second pressure chamber, the nozzle channel, thefirst communication channel, the second communication channel, and thefirst branch channel form an individual channel which is individuallyprovided with the nozzle, and wherein the first branch channelcommunicates with the nozzle channel at a position closer than the firstcommunication channel to the nozzle.
 2. The liquid ejecting headaccording to claim 1, wherein the first branch channel includes: a firstchannel that extends in the first direction and communicates with thefirst pressure chamber; and a second channel that extends in the seconddirection and enables the first channel and the nozzle channel tocommunicate with each other.
 3. The liquid ejecting head according toclaim 1, wherein the first pressure chamber and the nozzle channelextend in the first direction, and the first communication channelenables an end of the first pressure chamber on one side in the firstdirection and an end of the nozzle channel on another side in the firstdirection to communicate with each other.
 4. The liquid ejecting headaccording to claim 1, further comprising a second branch channel thathas a portion extending in the first direction and enables the secondpressure chamber and the nozzle channel to communicate with each otherthrough a path different from a path of the second communicationchannel.
 5. The liquid ejecting head according to claim 4, furthercomprising a third communication channel that enables the first branchchannel and the second branch channel to communicate with each otherthrough a path different from a path of the nozzle channel.
 6. Theliquid ejecting head according to claim 4, further comprising: a firstpartition wall that separates the first branch channel and the secondbranch channel; and a second partition wall that separates the firstcommunication channel and the first branch channel, wherein a thicknessof the first partition wall in the first direction is smaller than athickness of the second partition wall in the first direction.
 7. Theliquid ejecting head according to claim 4, wherein the first branchchannel and the second branch channel have a shared portion extending inthe second direction.
 8. The liquid ejecting head according to claim 1,further comprising: a supply channel which communicates with the firstpressure chamber and through which the liquid is supplied to the firstpressure chamber; and a discharge channel which communicates with thesecond pressure chamber and through which the liquid is discharged fromthe second pressure chamber.
 9. The liquid ejecting head according toclaim 1, further comprising: a supply channel which communicates withthe second pressure chamber and through which the liquid is supplied tothe second pressure chamber; and a discharge channel which communicateswith the first pressure chamber and through which the liquid isdischarged from the first pressure chamber.
 10. The liquid ejecting headaccording to claim 1, wherein the first branch channel includes a secondchannel that extends in the second direction and that communicates withthe nozzle channel, and an area of the second channel as viewed in thesecond direction is equal to an area of the first communication channelas viewed in the second direction.
 11. The liquid ejecting headaccording to claim 1, further comprising: a first energy-generatingelement that, upon application of a driving voltage, generates energyfor applying pressure to the liquid in the first pressure chamber; asecond energy-generating element that, upon application of a drivingvoltage, generates energy for applying pressure to the liquid in thesecond pressure chamber; and a drive circuit that applies a drivingvoltage to both the first energy-generating element and the secondenergy-generating element.
 12. The liquid ejecting head according toclaim 11, wherein the drive circuit is positioned, as viewed in thesecond direction, between the first energy-generating element and thesecond energy-generating element in the first direction.
 13. A liquidejecting apparatus comprising: the liquid ejecting head according toclaim 1; and a control section that controls liquid ejection operationof the liquid ejecting head.
 14. A liquid ejecting head comprising: afirst pressure chamber that applies pressure to a liquid; a secondpressure chamber that applies pressure to the liquid; a nozzle channelthat extends in a first direction and communicates with a nozzle thatejects the liquid; a first communication channel that extends in asecond direction crossing the first direction and enables the firstpressure chamber and the nozzle channel to communicate with each other;a second communication channel that extends in the second direction andenables the second pressure chamber and the nozzle channel tocommunicate with each other; a first branch channel that has a portionextending in the first direction and enables the first pressure chamberand the nozzle channel to communicate with each other through a pathdifferent from a path of the first communication channel; a pressurechamber substrate in which the first pressure chamber and the secondpressure chamber are provided; a communication plate in which the nozzlechannel, the first communication channel, the second communicationchannel, and the first branch channel are provided; and a nozzlesubstrate in which the nozzle is provided, wherein the first pressurechamber, the second pressure chamber, the nozzle channel, the firstcommunication channel, the second communication channel, and the firstbranch channel form an individual channel which is individually providedwith the nozzle.
 15. The liquid ejecting head according to claim 14,wherein wall surfaces of the first branch channel include a first wallsurface constituted by the pressure chamber substrate, and a second wallsurface positioned opposite to the first wall surface in the seconddirection and constituted by the communication plate.
 16. The liquidejecting head according to claim 14, wherein wall surfaces of the nozzlechannel include a third wall surface constituted by the communicationplate, and a fourth wall surface positioned opposite to the third wallsurface in the second direction and constituted by the nozzle substrate.17. A liquid ejecting head comprising: a first pressure chamber thatapplies pressure to a liquid; a second pressure chamber that appliespressure to the liquid; a nozzle channel that extends in a firstdirection and includes a nozzle that ejects the liquid; a firstcommunication channel that extends in a second direction crossing thefirst direction and enables the first pressure chamber and the nozzlechannel to communicate with each other; a second communication channelthat extends in the second direction and enables the second pressurechamber and the nozzle channel to communicate with each other; a firstbranch channel that has a portion extending in the first direction andenables the first pressure chamber and the nozzle channel to communicatewith each other through a path different from a path of the firstcommunication channel; a pressure chamber substrate in which the firstpressure chamber and the second pressure chamber are provided; acommunication plate in which the nozzle channel, the first communicationchannel, the second communication channel, and the first branch channelare provided; and a nozzle substrate in which the nozzle is provided,wherein wall surfaces of the first branch channel include a first wallsurface constituted by the pressure chamber substrate, and a second wallsurface positioned opposite to the first wall surface in the seconddirection and constituted by the communication plate.